Apple's iPhone 6 Touch ID has same fingerprint failings as 5s

John E. Dunn |
Sept. 25, 2014

The Touch ID fingerprint security that comes with Apple's iPhone 6 is no better at resisting sophisticated print-lifting attacks than the iPhone 5s on which the system made its debut, according to a researcher from mobile security firm Lookout.

The Touch ID fingerprint security that comes with Apple's iPhone 6 is no better at resisting sophisticated print-lifting attacks than the iPhone 5s on which the system made its debut, according to a researcher from mobile security firm Lookout.

The failing uncovered by principal security researcher Marc Rogers is probably best described as a theoretical weakness than a real worry but it does emphasise that the underlying insecurity of fingerprint systems remains live in some circumstances.

Rogers first obtained a usable fingerprint from the body of the iPhone, not easy given that it had to be unsmudged as well as the correct finger used to secure the system. The attacker needs both before the print can be lifted from the surface using a tricky procedure that sounds more like something from CSI than a hacking course.

The attacker also has to get the imposter fingerprint exactly right when pitting it against Touch ID - more than five incorrect attempts and the iPhone insists on a PIN number.

However, Rogers was still able to use the same technique that beat the iPhone 5s's Touch ID last year to fool the iPhone 6's equivalent. Given that it's hard to pull off does the weakness really matter?

It all depends on the expectation users have of iPhone 6 security, which represents an important part of the authentication process for the Apple Pay contactless payment system the computer giant wants the new iPhone to promote.

Improvements in Touch ID include greater sensitivity (i.e where the sensor rejects a legitimate fingerprint), something that boosts ease-of-use. However, the potential for a targeted attack remain possible.

"Sadly there has been little in the way of measurable improvement in the sensor between these two devices. Fake fingerprints created using my previous technique were able to readily fool both devices," said Rogers.

"The attack requires skill, patience, and a really good copy of someone's fingerprint any old smudge won't work," he said. "That said, I can't help but be a little disappointed that Apple didn't take this chance to really tighten up the security of Touch ID."

These security of these systems could be boosted dramatically by simply insisting on PINs in addition to fingerprints but this would kill the whole point of fingerprint systems - they are quick and convenient.